Question of the Day - PWI vs. HBCU

As someone that has been blessed enough to attend both a PWI (undergrad) and an HBCU (graduate), I can see where there is a difference between the two (by difference I’m not pertaining to equivalence in grading between the two). The major difference that I see is that HBCU professors tend to genuinely care more about their students as far as it comes to learning the material and passing classes. At a PWI you are basically on your own, they (some) could care less if you pass or fail. I enjoyed my experience at my PWI, but I feel I’ve gained way more by attending an HBCU. Yesterday a screenshot of a tweet surfaced all over social networks and raised many eyebrows. The tweet stated, “A 4.0 at a HBCU is not equivalent to a 4.0 at a rigorous PWI”. So I have to ask, is there a difference in grading at a PWI vs. an HBCU?